Conventional pyroelectric infra-red (PIR) motion sensors, also known as passive infra-red motion sensors, can be used to sense mid-IR range radiation emitting from a person in the range of the PIR motion sensor. However, conventional PIR motion sensors also output false positive signals due to transient rays of light from the sun. For example, when transient rays of light from the sun go through a window, inside a building, and impinge on a conventional indoor PIR motion sensor, a false output signal can result. A false signal can also be generated when transient rays of light from the sun impact a conventional PIR motion sensor that is mounted outdoors. For these reasons, conventional PIR motion sensors are often used inside, or outside at night when sunlight is not present, such as to turn a light on when someone is nearby. A conventional approach is to complement the conventional PIR motion sensors with another sensing technology which is not affected by light, such as 10.525 GHz radar.